What's so great about the Great American Eclipse?

If you are a Tri-State resident, you likely have heard at least something about the solar eclipse that will occur next month.

That's because the eclipse on Aug. 21 will be a total solar eclipse — something that hasn't happened in the United States in nearly four decades — lasting its longest near Carbondale, Illinois and reaching its point of total eclipse near Hopkinsville, Kentucky with a 0.1 second difference in time between those points.

For 2 minutes and 40 seconds, the moon will completely block out the sun in those locations. Everywhere else outside of the path the moon will travel as it obscures the sun as seen from North America on Aug. 21 will experience it as a partial eclipse.

The two cities are within driving distance of Evansville and have been counting down the days, hours and minutes to the eclipse with marketing campaigns capitalizing on their ideal locations to view what is being nationally as the "Great American Eclipse."

What's so great about it?

Lots of things. The 2017 total solar eclipse will traverse the entire United States, so it will be visible in its entirety in parts of 14 states. It has been 99 years since the last time that happened. On June 8, 1918, a total solar eclipse crossed the country from Oregon to Florida. The 1979 total solar eclipse passed through five northwestern states.

The 2017 eclipse paths will stretch from Lincoln Beach, Oregon to Charleston, South Carolina, according to NASA. The American government space agency maintains a detailed eclipse 2017 website, including maps of the eclipse's path.

This shirt being sold by the Hopkinsville convention and visitors bureau marks the upcoming total solar eclipse on Aug. 21. Both Hopkinsville, Ky., and Carbondale, Ill,, should be prime spots to watch the event.(Photo: Provided photo)

Eclipse path map.(Photo: NASA)

Those inside the eclipse's path of totality — that is the path the moon's shadow makes on the Earth as it moves across the sun — will be able to watch as the moon slowly covers the sun until it is completely blocked.

In Evansville, just north of the eclipse path, residents will still experience a 99.17 percent eclipse at its maximum, said Mathew Merlo, visiting professor of physics at the University of Southern Indiana. That's pretty dark for an early summer afternoon.

"It will be about like twilight," Merlo said.

Whether they are total, partial or annular (when the moon doesn't appear big enough to completely cover the bright area of the sun), solar eclipses are not rare planet-wide.

What makes them rare, Merlo said, is where they occur and that they only cover small geographical areas when they happen.

"It really is a once or twice in a lifetime event for a lot of people," he said.

In Evansville, the partial eclipse will begin at 11:55 a.m. and end at 2:49 p.m., according to NASA. Maximum eclipse will occur at 1:24 p.m.

"We've waited a long time in North America," said Mitch Luman, director of science experiences at the Evansville Museum of Arts, History and Science.

Luman said solar eclipses appeal to something inside people.

"It's so out of your ordinary experience. It sort of catches your soul off guard," he said.

Both Merlo and Luman are planning to use the eclipse as a launching pad for interest in science.

"It's something interesting to look at. It's a good chance to get people interested in astronomy," Merlo said.

USI will host a public eclipse viewing from 11 a.m. to 3 p.m. Aug. 21, providing eclipse sunglasses and access to telescopes with solar filters to protect eyes from the potentially harmful effects of gazing at the sun.

The Evansville Museum will have an Eclipse 2017 exhibition where visitors can learn more about eclipses and where and how to safely view it. The exhibit will be open July 27 - Sept. 31.

Although total solar eclipses have been a rarity for recent generations in the United States — just five since 1970 — that will change somewhat with five total solar eclipses set to occur somewhere in the U.S.. However, none of them will cross the entire country again and one will just be visible in a small part of Alaska.

Tri-State residents won't have to travel far to experience the next one. On April 8, 2024, a total solar eclipse will be visible from Texas to Maine along a path crossing over Evansville and much of Indiana.

The eclipse 2024 path will cross the eclipse 2017 path near Carbondale, although it will have reached its points of greatest eclipse and greatest duration in central Mexico.